The class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon has been known for some time. Nozaki, e.g., U.S. Pat. No. 3,694,412, produced such polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. More recent processes for the production of the linear alternating polymers, now known as polyketones or polyketone polymers, are illustrated by a number of published European Patent Applications including Nos. 121,965, 181,014, 213,671 and 257,663. These processes generally involve contacting the reactants under polymerization conditions in the presence of a reaction diluent and a catalyst composition formed from a compound of palladium, cobalt or nickel, the anion of a strong non-hydrohalogenic acid and a bidentate ligand of phosphouus, arsenic, antimony or nitrogen.
The polyketones are relatively high molecular weight materials having established utility as premium thermoplastics. The polyketone polymers are processed by methods conventional for thermoplastics, e.g., injection molding, extrusion or thermoforming, into a variety of shaped articles such as containers for food or drink.
The scope of the polymerization process is extensive, but without wishing to be limited, a preferred process employs an alkanol reaction diluent, particularly methanol, and a catalyst composition formed from a compound of palladium, the anion of a non-hydrohalogenic acid having a pKa below 2 and a bidentate ligand of phosphorus. The choice of the individual precursors of the catalyst composition has a considerable impact upon the polymerization process, as does the choice of the reaction environment, a term usually referring to the materials present in the reaction mixture in addition to the reactants and catalyst composition components. In most cases, the reaction environment usually refers to the reaction diluent. The polymer product is not often appreciably soluble in the reaction diluent and is observed as a slurry in the diluent. It is in part because of the observation of a "slurry of product" that batch or semi-continuous processes for polyketone production are referred to as slurry-phase processes.
The choice of reaction diluent also has a substantial effect on the polymerization process and in particular upon the polymerization rate. In many, if not most instances, a protic solvent provides faster reaction rates, particularly when lower alkanols such as methanol are used as the reaction diluent. However, the use of mixtures of aprotic solvents and alcohols is disclosed by van Broekhoven et al, U.S. Pat. No. 4,877,860, and the use of mixtures of aprotic solvents and water is shown by Wong, U.S. Pat. No. 4,940,774. A somewhat different reaction environment is exemplified by U.S. Pat. No. 4,835,250 (equivalent to EP 121,965) wherein a diethylene glycol and molecular hydrogen were employed. It would be of advantage, however, to provide an additional reaction environment for the production of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon.